Confirmation of the utility of fine needle aspiration biopsy of the renal allograft.

Allograft immunobiologic theory would predict that analysis of immunocompetent cells infiltrating the renal transplant would be most instructive. Recently a new aspiration biopsy technique has been developed to permit such analysis in patients which can be safely and repetitively performed. The clinical utility of such a technique has been tested utilizing a randomized prospective trial in which an aspirate was obtained every other day from the third post-operative day until discharge. Analysis included examination of adequacy criteria and the capacity of pathologic diagnosis to corroborate clinical diagnosis from coded specimens. Ninety-six aspirates from 21 consenting transplant recipients were obtained and analyzed. In 94 instances a clinical diagnosis could be made; 80 aspirates fulfilled adequacy criteria. We found the technique to be highly sensitive (greater than or equal to 90%) and highly specific (greater than or equal to 90%) for the clinical diagnoses of acute allograft rejection, post-operative acute renal failure, cyclosporine toxicity, and normal function. We conclude that the fine needle aspiration technique is an important adjunct to analysis of clinical renal transplantation and offers a major advantage to the clinical scholar in understanding transplant biology.